"Everyone knows, even the smallest kid knows about Martin Luther King, can say his most famous moment was that 'I have a dream' speech," said Henry Louis Taylor Jr., professor of urban and regional planning at the University of Buffalo.
"No one can go further than one sentence," he said. "All we know is that this guy had a dream, we don't know what that dream was."
At the time of his death, King was working on antipoverty and antiwar issues.
He had spoken out against the Vietnam War in 1967, and was in Memphis in April 1968 on behalf of striking sanitation workers. King had come a long way from the crowds who cheered him at the 1963 March on Washington, when he was introduced as "the moral leader of our nation" - and when he pronounced "I have a dream" on the steps of the Lincoln Memorial.
By taking on issues outside segregation, he had lost the support of many newspapers and magazines, and his relationship with the White House had suffered, said Harvard Sitkoff, a professor of history at the University of New Hampshire who wrote a recently published book on King.
"He was considered by many to be a pariah," Sitkoff said.
But he took on issues of poverty and militarism because he considered them vital "to make equality something real and not just racial brotherhood but equality in fact," Sitkoff said.
While there has been scholarly study of King and everything he did, that knowledge hasn't translated into the popular culture perception of him and the civil rights movement, said Richard Greenwald, professor of history at Drew University in Madison, N.J.
"We're living increasingly in a culture of top 10 lists, of celebrity biopics which simplify the past as entertainment or mythology," he said. "We lose a view on what real leadership is by compressing him down to one window."
That does a disservice to King and society, said Melissa Harris-Lacewell, professor of politics and African-American studies at Princeton University.
By freezing him at that point, by putting him on a pedestal of perfection that doesn't acknowledge his complex views, "it makes it impossible both for us to find new leaders and for us to aspire to leadership," Harris-Lacewell said.
